In modern water purification plants large quantities of sludge are produced which, among other things, contains phosphorus for which plants in the natural world have a need. Phosphorus is a finite resource and it is therefore desirable to have the facility for recycling sewage sludge, for example on arable land. There is therefore a need to be able to effectively treat the sludge which contains a number of substances harmful to humans and the environment, such as heavy metals and oil. The sludge moreover has a high bacteria content, which is undesirable.
Not only sewage sludge, but other masses also need to be cleansed of the aforementioned pollutants before they can be returned to nature, for example soil from industrial land.
The purification of polluted masses using modern technology requires large quantities of water, which must be disposed of, as is also the case with industrial process water. It is also desirable, therefore, to be able to treat such water in an environmentally friendly way so that it can be reused.